(1) Field of the invention
The present invention rotates to a washing machine to be used for washing and cleaning of items to be washed, heavily soiled and required to be washed collectively in a large amount, such as iron plates and tableware for grilled meat employed in restaurants, shopping baskets used in supermarkets, bottle cases for transport employed for carrying a plurality of bottles, hooks for suspending items to be painted used in painting processes, etc.
(2) Description of prior arts
To the iron plates for grilled meat employed in restaurants, oily component and carbonized substances etc. of cooking materials tend to adhere strongly, and due to the fact that such iron plates are used in a large number, excessive labor and expenses are required if normal labor is required in the washing of such objects to be washed. Meanwhile, the tableware used in restaurants, shopping baskets employed in supermarkets, transport bottle cases used for carrying a plurality of bottles, hooks for suspending items to be painted, employed in the painting processes, etc. are also used in a large number and easily soiled and extreme difficulties have been involved in the washing and cleaning work thereof.
Conventionally, as washing machines for removing such adhering substances, there have been known several arrangements employing rotary brushes, for example, in Japanese Utility Model Laid-Open Publication Jikkosho No. 55-41331, and Japanese Patent Laid-Open Publications Tokkaisho Nos. 55-59873, 56-33073 and 59-82983, etc.
However, in the washing machine employing a rotary brush, if the surface of the object to be washed has undulation or concave and convex portions, cleaning of narrow portions by the brush tends to be insufficient, and there has been such a problem that solid or cubic items such as the tableware, shopping baskets, transport bottle cases, etc. can not be fully washed by brushes.
Meanwhile, there has also been known a washing machine arranged to spray a detergent liquid onto the objects to be washed such as tableware and the like as in a dish washer, but such a conventional machine can not fully display its cleaning effect in the case of stain strongly sticking as in the adhering items referred to earlier.
In order to overcome the disadvantage in the washing action by the liquid detergent alone as described above, various washing apparatuses adapted to spray liquid detergent mixed with particles of polishing material onto the objects to be washed, have been proposed, for example, in Japanese Patent Publication Tokkosho No. 53-4339, and Japanese Patent Laid-Open Publications Tokkaisho Nos. 53-27273 and 54-54459, etc. The prior arts as referred to above, however, are still insufficient in the cleaning function with respect to the objects having soiled, and it is also difficult to efficiently remove the strongly sticking adhering items. Moreover since the liquid detergent must be used in a large amount, much running cost is involved, while a problem related to discharge of the detergent liquid after use must also be brought into consideration.
It is to be noted here that performing the surface finish such as rust removal and the like by directing shot materials onto surfaces of metallic products through employment of a centrifugal blasting unit is conventional, but such a practice, if applied to washing as it is, has an excessively strong polishing action, with a possibility of injuring the objects to be washed, and thus, can not be directly used for the actual applications.